This invention relates to a novel compound, 1-methacryloxyethane-1,1-diphosphonic acid and its salts, used as a polymerizable monomer in a dental adhesive composition.
For the treatment of dental caries, composite resins were developed as a substitute for conventional dental cements such as zinc phosphate cement and silicate cement. Recently, improved composite resins are available which are to be stable for a prolonged period of time, because of reduced water-absorption and degradation, and exhibit very little difference in color from natural teeth.
However, since composite resins do not essentially adhere to tooth enamel or dentin, there is a likelihood that a gap will be formed between tooth cavity and composite resin embedded therein over a long period of time. Such a gap tends to facilitate secondary caries and eventually a filled composite resin will fall from the cavity.
To improve the adhesion between the composite resin and the cavity wall, a variety of adhesion promotors or adhesive liners were developed. Also proposed were adhesive caries-preventive filling materials, malaligned tooth orthodontic adhesives, and other dental adhesive compositions which solely aim at firm adhesion to tooth substances. Most of them have problems with respect to durability in the mouth and ease of handling and few materials can firmly adhere to tooth for a long period of time in a wet, temperature-varying environment like the mouth.